Re: How git affects kernel.org performance

On Mon, Jan 08, 2007 at 02:59:52PM +0100, Pavel Machek wrote:

Hi!

quoted

quoted

Would e2fsck -D help? What kind of optimization
does it perform?

It will help a little; e2fsck -D compresses the logical view of the
directory, but it doesn't optimize the physical layout on disk at all,
and of course, it won't help with the lack of readahead logic.  It's
possible to improve how e2fsck -D works, at the moment, it's not
trying to make the directory be contiguous on disk.  What it should
probably do is to pull a list of all of the blocks used by the
directory, sort them, and then try to see if it can improve on the
list by allocating some new blocks that would make the directory more
contiguous on disk.  I suspect any improvements that would be seen by
doing this would be second order effects at most, though.

...sounds like a job for e2defrag, not e2fsck...

I wasn't proposing to move other data blocks around in order make the
directory be contiguous, but just a "quick and dirty" try to make
things better.  But yes, in order to really fix layout issues you
would have to do a full defrag, and it's probably more important that
we try to fix things so that defragmentation runs aren't necessary in
the first place....

						- Ted